Free tools
Implied Probability Calculator
Turn one price into the win rate it implies, or turn a win probability into the fair odds.
Free, no account needed. Informational, not betting advice. 21+.
Results
- Implied probability
- 40.00%
- Fair odds (American)
- +150
- Fair odds (decimal)
- 2.50
- Fair odds (fractional)
- 3/2
Win 40 of 100 bets like this to break even.
How it works
Implied probability is the break-even win rate baked into a price. For decimal odds it is 1 divided by the price. For a minus American price it is the odds divided by the odds plus 100. For a plus price it is 100 divided by the odds plus 100. Going the other way, fair decimal odds are 1 divided by the probability.
Worked example
+150 is decimal 2.50, so it implies 40%. If you believe the true chance is 45%, the fair price is 1 ÷ 0.45 = 2.22, or −122. The +150 on offer would be the better price.
When to use it
Use it after a check when you want to compare the price on your slip with your own estimate, or when you want to know the win rate a price demands before you take it.
Questions
Is implied probability the true probability?
No. It includes the book’s margin, so both sides of a market add to more than 100%. The No-Vig tool strips that margin and gives a fair probability.
What is a fair price?
The odds that match a probability with no margin added. At 50% the fair price is +100. EdgeFast’s checks estimate it from the listed books when every leg matches.
Why does 50% show as +100 and not −100?
They are the same price. The tool shows the plus form for even money.
Which should I trust, my probability or the market?
The market is a strong starting point, and the sharpest books move the least. Treat your own number as a hypothesis and keep a record of how it holds up over time.
Is this betting advice?
No. The tool is arithmetic on the numbers you type. EdgeFast is informational price discovery, not a sportsbook, and you decide whether to bet. 21+ only.
Related tools
Now check a real price.
Screenshot a betslip and EdgeFast compares your price with the listed sportsbooks and a fair market price.
Informational, not betting advice. 21+.